Referring to FIG. 1, a block diagram of a circuit 10 is shown illustrating a conventional power supply implemented in a Universal Serial Bus (USB) environment (such as a device in compliance with the Universal Serial Bus Specification, Version 1.1, published September 1998 and the Universal Serial Bus Specification, Version 2.0, published April 2000, both of which are incorporated by reference). The circuit 10 comprises a power supply portion 12, a USB input/output (USB I/O) 14 and a bus portion 16. The power supply portion 12 and the USB I/O portion 14 are implemented on a single device. The power supply 12 presents a constant 3.3V power supply to the USB I/O 14. The power supply 12 does not provide a low power standby mode. The bus portion 16 comprises a resistor R1, a resistor R2 and a resistor R3. The resistor R1 is implemented as a 7.5KΩ resistor. The resistor R2 is implemented as a 15KΩ resistor. The resistor R3 is implemented as a 15KΩ resistor.
A source of the resistor R1 receives a voltage signal VBUS. The voltage signal VBUS is a 5V nominal supply voltage. The drain of the resistor R1 is coupled to a node D+. A source of the resistor R2 is coupled to the node D+. A drain of the resistor R2 is coupled to ground. A source of the resistor R3 is coupled to a node D−. A drain of the resistor R3 is coupled to ground. Additionally, the USB I/O portion 14 is coupled to the node D+ and the node D−. The USB I/O 14 is configured to communicate with the bus portion 16. The USB I/O 14 and the bus portion 16 are not configured to operate in a low power standby mode.